J/A+A/557/A81 XMM-LSS field X-ray sources classification (Melnyk+, 2013)
Classification and environmental properties of X-ray selected point-like sources
in the XMM-LSS field.
Melnyk O., Plionis M., Elyiv A., Salvato M., Chiappetti L., Clerc N.,
Gandhi P., Pierre M., Sadibekova T., Pospieszalska-Surdej A., Surdej J.
<Astron. Astrophys. 557, A81 (2013)>
=2013A&A...557A..81M 2013A&A...557A..81M
ADC_Keywords: X-ray sources ; Active gal. nuclei ; QSOs ; Redshifts
Keywords: quasars: general - X-rays: general - galaxies: active -
X-rays: galaxies
Abstract:
The XMM-Large Scale Structure survey (XMM-LSS), covering an area of
11.1 sq. deg., contains more than 6000 X-ray point-like sources detected
with XMM-Newton to a flux of 3x10-15erg/s/cm2 in the [0.5-2]keV
band. The vast majority of these sources have optical (CFHTLS),
infrared (SWIRE IRAC and MIPS), near-infrared (UKIDSS) and/or
ultraviolet (GALEX) counterparts.
We wish to investigate the environmental properties of the different
types of the XMM-LSS X-ray sources by defining their environment using
the i'-band CFHTLS W1 catalog of optical galaxies to a magnitude limit
of 23.5mag.
We have classified 4435 X-ray selected sources on the basis of their
spectra, SEDs, and X-ray luminosity, and estimated their photometric
redshifts, which have a 4-11 band photometry with an accuracy of
sigmadz/(1+zsp)=0.076 with 22.6% outliers for i'<26mag. We
estimated the local overdensities of 777 X-ray sources that have
spectro-z or photo-z calculated by using more than seven bands
(accuracy of sigmadz/(1+zsp)=0.061 with 13.8% outliers) within the
volume-limited region defined by 0.1<z<0.85 and -23.5<Mi'←20.
Although X-ray sources may be found in variety of environments, a high
fraction (∼55-60%), as verified by comparing with the random
expectations, reside in overdense regions. The galaxy overdensities
within which X-ray sources reside show a positive recent redshift
evolution (at least for the range studied; z<0.85). We also find that
X-ray selected galaxies, when compared to AGN, inhabit significantly
higher galaxy overdensities, although their spatial extent appear to
be smaller than that of AGN. Hard AGN (HR>-0.2) are located in more
overdense regions than soft AGN (HR←0.2), which is clearly seen in
both redshift ranges, although it appears to be stronger in the higher
redshift range (0.55<z<0.85). Furthermore, the galaxy overdensities
(with δ>1.5) within which soft AGN are embedded appear to evolve
more rapidly compared to the corresponding overdensities around hard
AGN.
Description:
Table 2 presents the spectroscopic and/or photometric redshifts for
5142 X-ray selected sources in the XMM-LSS field which have an optical
counterpart.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 109 4206 Parameters of X-ray sources
refs.dat 149 15 References
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See also:
J/A+A/474/473 : XMM-LSS survey: AGN classifications (Garcet+, 2007)
J/MNRAS/429/1652 : XMM-LSS catalogue. Version II. (Chiappetti+, 2013)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- 2XLSSd 2XLSSd name (JHHMMSS.s+DDMMSS)
17 A1 --- m_2XLSSd [ab] Multiplicity index on 2XLSSd
19- 26 F8.5 deg RAdeg Optical counterpart Right ascension (J2000.0)
28- 35 F8.5 deg DEdeg Optical counterpart declination (J2000.0)
37- 42 F6.4 --- zsp ?=9.9999 spectroscopic redshift when available
44 I1 --- q_zsp Rank of the spectroscopic redshift (1)
46- 51 A6 --- r_zsp Source of the spectroscopic redshift,
in refs.dat file (2)
53- 59 A7 --- spCl Spectral classification:
AGN, GAL, GAL/AGN, QSO, QSO2, STAR
61- 66 F6.4 --- zph ?=9.9999 Photometric redshift
68- 74 A7 --- sedCl Classification according to SED (3)
76 I1 --- q_zph Rank of the photometric redshift (4)
78- 82 F5.2 --- HR [-1/1] Hardness ratio
84- 92 E9.3 10-7W LXsoft ?=0 X-ray luminosity in the soft band (erg/s)
94-102 E9.3 10-7W LXhard ?=0 X-ray luminosity in the hard band (erg/s)
104-107 A4 --- Cl Final classification of the source:
AGN, GAL, QSO or STAR
109 I1 --- dog [0/1] 1 = DOG object (Dust Obscured Galaxy)
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Note (1): Spectroscopic redshift quality code:
1 = good quality (two or more lines in the spectra)
2 = acceptable redshifts (one clear line in the spectra)
3 = dubious redshift
9 = unknown or does not exist
Note (2): The compilation of redshifts from 7-14 can be found here:
http://www.nottingham.ac.uk/~ppzoa/UDS_redshifts_18Oct2010.fits
Note (3): classification according to SED:
GAL = normal galaxy templates of Ilbert et al. (2009ApJ...690.1236I 2009ApJ...690.1236I)
or templates #1-6 of Salvato et. al (2009ApJ...690.1250S 2009ApJ...690.1250S)
AGN/QSO = hybrid and AGN/QSO templates (#7-30) of
Salvato et al. (2009ApJ...690.1250S 2009ApJ...690.1250S)
Note (4): Photometric redshift quality code:
1 = good quality photometric redshift: 7 or more bands, PDZ=100
2 = medium quality photometric redshift: 7 or more bands, PDZ<100
3 = dubious photometric redshift, 4-6 bands
4 = no redshift because of lack of photometry
5 = no redshift because the objects are invisible (very faint) or
wrong associations (probably misclassified)
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode BibCode
24- 43 A20 --- Aut Author's name
45-149 A105 --- Com Comments
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Acknowledgements:
Olga Melnyk, melnykol(at)gmail.com
(End) Olga Melnyk [Liege, Belgium], Patricia Vannier [CDS] 06-Aug-2013